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Causality Aspects of the Parton Cascade Approach to Ultarelativistic Heavy Ion Reactions

Cornelius C. Noack
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Abstract

Parton cascade models have been surprisingly successful in describing heavy-ion reactions at RHIC energies -- surprising because in spite of their QCD bells and whistles, they essentially embody classical many-particle dynamics. The procedure to determine the sequence of the binary parton interactions, however -- an essential aspect of all such models -- is by necessity a phenomenological (and somewhat arbitrary) feature of these codes. This has been recognized early on as a serious drawback of non-covariant cascade models. While in the Poincare-Covariant Parton Cascade code "pcpc" the interaction sequence is determined covariantly and thus is independent of the frame of reference in which the code is run, this alone does not solve the basic causality problems raised by such classical models. We discuss in detail all aspects of (Einstein) causality encountered in such parton cascade models.

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Cornelius C. Noack. 2003-12-29. Causality Aspects of the Parton Cascade Approach to Ultarelativistic Heavy Ion Reactions. https://arxiv.org/abs/hep-ph/0312365

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